1. Field of the Invention
The present invention relates to a function addition apparatus and a function addition method for adding functions to a computer and, more particularly, to a function addition apparatus and a function addition method for adding a function to a computer before an operating system installed on the computer is started.
2. Description of the Related Art
In recent years, a personal computer allowing a user to enjoy TV programs and to record/reproduce them has emerged. Such a personal computer is provided with a TV tuner for receiving TV programs and a hard disk drive and a DVD (Digital Versatile Disc) drive for recording/reproducing TV programs.
Further, there is an invention that encrypts a hard disk drive in a personal computer and incorporates an encryption key and a program for decrypting the code into an expansion board to be inserted into an extension slot of the personal computer (refer to, for example, Jpn. Pat. Appln. Laid-Open Publication No. 2003-330726). According to the above invention, the code of the hard disk drive can be broken by the code-breaking program called by a BIOS (Basic Input/Output System) or an operating system when the extension board is inserted into the extension slot; whereas it is impossible to break the code of the hard disk drive in a state where the extension board is not inserted into the extension slot.
The above TV function of a personal computer becomes effective when an operating system or an application program that operates on the operating system controls the TV tuner, hard disk drive, and DVD drive after start-up of the operating system. However, the start-up of the operating system is normally completed after a good length (e.g., three minutes) of time has elapsed since the computer was powered on or reset. Therefore, it is impossible for a user to enjoy a TV program as soon as he or she switches on a computer, unlike the case of a normal TV set.
There is available a personal computer designed for solving the above program. This personal computer incorporates two TV tuners. One TV tuner can be operated through an operating system or an application program. The other TV tuner is configured as a stand-alone TV tuner. However, in such a personal computer, a TV program received by the stand-alone TV tuner cannot be recorded on a built-in or external hard disk drive or a DVD disc in a built-in or external DVD drive.
The above problem is also recognized in reception and recording/reproduction of radiobroadcast or reception and recording/reproduction of data.